In general, a Navigation Satellite System (NSS) refers to a position determining system that utilizes satellite-based position determining components or possibly a variety of terrestrial-based and satellite-based position determining components to determine a geographic position.
In one embodiment, the geographic position provided by the NSS describes the latitude and longitude at the receiving device's location. However, NSS's may also be used to determine elevation, speed, time, and the like. In most cases, the navigation satellite systems are global (e.g., GNSS), however, there are also NSS's that are regional (e.g, RNSS), local (e.g., LNSS) and the like. The present technology is well suited for use in one or a combination of NSS environments.
An NSS comprises a system of satellites that transmit information from which an observer's present location and/or the time of observation can be determined. GPS is one such GNSS, however the Russian Global Orbiting Navigational System (GLONASS), is an alternative or supplemental system and the European Galileo, the Indian Regional Navigational Satellite System (IRNSS), and Chinese Compass systems are also under development.
For ease of terminology the present application will refer to a Global Navigation Satellite System or GNSS, to refer to GPS, GLONASS, and to other satellite-based system that provides information by which an observer's position and the time of observation can be determined.
In particular, a GNSS uses the transmission of coded radio signals from a family of earth-orbiting satellites (up to 32 satellites for GPS) to calculate a receiver's position. A GNSS antenna receives GNSS signals from a plurality (preferably four or more) GNSS satellites and passes these signals to a GNSS signal receiver/processor, which identifies the GNSS satellite source for each GNSS signal, determines the time at which each identified GNSS signal arrives at the antenna, and determines the present location of the GNSS satellites, from which the receiver's location is calculated.
For example, in one embodiment the positions received from GNSS receivers, computed while the receiver's antenna is in a certain physical situation, can be recorded. This information can be used as observations for topographical surveying, mapping, set-out functions and the like.